It is often desirable to fix the spacing between two bearings. For example, consider a hub of a heavy transport vehicle such as a truck or locomotive. The hub comprises a substantially cylindrical billet of metal having an axially extending hole through which an axle of the vehicle can pass. Opposite ends of the hole are machined to have an enlarged diameter to seat the cup of a tapered bearing. When assembling the hub and attaching it to the axle, the tapered bearing on the abutment side of the hub is packed with grease or lightly oiled and a lubricant seal placed adjacent to the tapered bearing. The hub is then slid over the axle and typically the remainder of the central hole filled with grease or other lubricant. The other tapered bearing is then packed with grease, placed into its cup and a bearing lock nut screwed onto a thread formed about the end of the axle to lock the hub onto the axle. It is however important that the lock nut not be over-tightened, nor be too loose. If the nut is over-tightened, the free rotation of the hub will be hampered and there will be excessive wear of the bearings. If however the lock nut is too loose, there may be excessive play in the hub and wheel and the seals about the bearings can work loose resulting in a loss or contamination of lubricant and accelerated wear of the bearings.
In order to avoid these problems, it is known in the prior art to pack the hole of the hub with a plurality of spacers and shims to fix the distance between the opposite tapered bearings. However this is a time consuming process. Also, the distance between the tapered bearings can only be adjusted in increments equivalent to the width, of the shims. The prior art methods of adjusting the spacing between the tapered bearings also requires the use of specialized measurement equipment which is expensive, can easily lose its accuracy if roughly handled, and requires considerable training in order to be used.